Dome construction

ABSTRACT

A dome construction having structural frame members arranged in a polygonal pattern forming framed openings covered by sheet material, and a novel joint construction at each frame member for supporting and retaining edge margins of adjacent sheets of material by a single retainer member and a pair of gasket elements urged by said retainer member into wedging and sealed relation with the edge margins of the sheets of material. A dome construction having a novel arrangement of structural frame members in which certain frame members in pentagon pattern are located to enhance structural efficiency.

United States Patent 1191 Richter 1 Oct. 7, 1975 DOME CONSTRUCTION [75] Inventor: Donald L. Richter, Harbor City,

Calif.

3,531,899 11/1970 Bartlett 52/469 3,686,721 8/1972 Nelson 3,791,088 11/1971 Sandow...

3,830,033 8/1974 Gahler 160/391 Primary Examiner-Ernest R. Purser Assistant Examiner-Henry Raduazo Attorney, Agent, or Firm-Edward F. Jams 52] US. Cl. [57] ABSTRACT [51] Int. Cl. E04B 1/347 A dome construction having structural frame mem- [58] Field of Search 52/63, 222, 2, 469; bers arranged in a polygonal pattern forming framed 24/243 K; 160/391, 392, 395, 397, 394, 399, openings covered by sheet material, and a novel joint 402 construction at each frame member for supporting and retaining edge margins of adjacent sheets of mate- [56] References Cited rial by a single retainer member and a pair of gasket UNITED STATES PATENTS elements urged by said retainer member into wedging 1,076,767 10/1913 JhIlSOl'l.... 160/397 and Sealed relation with the edge margins of the Sheets 1,897,418 2/1933 Carlson g H 160/397 of material. A dome construction having a novel ar- 2,726,056 12/1955 Tammw 1 0 395 rangement of structural frame: members in which cer- 3,059,655 /1962 Bird 1 52/2 tain frame members in pentagon pattern are located to 3,088,559 5/1963 Farnsworth... 160/399 enhance structural efficiency. 3,199,258 8/1965 Tentoft 52/222 3,483,879 12/1969 06111111611 160/395 9 Claims, 11 Drawing Figures 5O 52 54 62 54 34 46 48 65 27 W7 58 d 27 35 a W 57/ 5/ 5 15/ K4? Q2 Sheet 1 of 3 3,909,994 V US. Patent Oct. 7,1975

US Patsnt Oct. 7,1975 Sheet 2 of 3 WWII/III);

US. Patent 0a. 7,1975 Sheet 3 of 3 3,909,994 I DOME CONSTRUCTION BACKGROUND OF INVENTION Geodesic-type dome construction which provide part spherical domes having clear spans of up to 25. feet or more include a plurality of triangulated space trusses in which structural frame members may be made of a lightweight metal such as aluminum alloys and in which the triangular framed openings may be covered by sheets of lightweight material such as aluminum, plastic materials, and the like. The triangulated structural pattern has included a hexagonal arrangement of six equilateral triangles in combination with a pentagonal arrangement of five equilateral triangles as described in Fuller U.S. Pat. No. 2,682,235 and Gelsavage US. Pat. No. 2,918,992. Assembly of structural frame members with triangular sheets of material has been described in my U.S. Pat. No. 3,477,752 in which ajoint construction between a structural frame member and adjacent sheets of material uses a pair of locking members disposed on opposite sides of a high center rib.

The present invention contemplates a geodesic-type dome construction provided with structural improvements in the arrangement of the triangulated truss structural members and in the assembly of the triangular sheets of material with such structural members.

SUMMARY OF INVENTION This invention relates to a novel geodesic-type dome construction in which structural frame members are arranged to provide more efficient stress conditions and to provide an effective efficicnt connection between structural frame members and sheets of material supported thereby and secured thereto. The invention particularly relates to a geodesic-type dome construction which for the same structural section of the frame members is capable of supporting greater dead and live loads than in prior proposed constructions.

An object of the invention is to provide a geodesic type dome construction which incorporates novel improvements in the arrangement of the structural frame members and in the manner of interconnection of the structural frame members and sheet material.

Another object of the present invention is to provide a joint construction adapted to cooperate with edge margins of sheet material in a novel manner.

Another object of the invention is to provide a dome construction in which a novel joint construction between structural frame members and sheet material affords not only an effective connection but also provides a convenient rapid means of assembly of the dome construction.

A still further object of the invention is to provide a joint construction readily adaptable to securing and retaining sheet material of different thickness.

A still further object of the present invention is to provide a dome construction wherein the polygonal arrangement including a plurality of pentagons located around the base periphery of the dome construction provides means for improving the stress conditions of the frame support members so that the size of the dome construction may be readily varied.

Generally speaking, a geodesic dome construction contemplated by this invention includes a plurality of frame members arranged in polygonal pattern, certain of said frame members adjacent the base being arranged in a pentagonal configuration at the base of each line of structural frame members which pass through the apex of the dome construction. Each frame member supports adjacent edge margins of sheet material. A single retainer member carrying gasket elements along each side is securable to the frame member and simultaneously urges the spaced resilient gasket elements into wedged pressure contact with edge margins of the sheet material. The gasket elements afford a tight pressure seal between the sheet edge margins and the retainer member.

Various other objects and advantages of the present invention will be readily apparent to those skilled in the art from the following description of the drawings in which exemplary embodiments of the invention are shown.

IN THE DRAWINGS FIG. 1 is a schematic top plan view of a dome construction embodying the present invention.

FIG. 2 is an enlarged fragmentary side elevational view of the structure shown in FIG. 1.

FIG. 3 is an enlarged fragmentary plan view with portions of the structure broken away illustrating means for joining a plurality of structural frame members and sheet material supported thereby at a common intersection area.

FIG. 4 is a fragmentary vertical sectional view taken in the plane indicated by line IIVIV of FIG. 3.

FIG. 5 is a fragmentary vertical sectional view taken in the planes indicated by line VV of FIG. 3.

FIG. 6 is an enlarged fragmentary transverse sectional view of a joint construction embodying this invention, the section being taken in the planes indicated by lines VlVI of FIG. 1.

FIG. 7 is an enlarged fragmentary sectional view of a joint construction in which one of the panels has greater thickness than the adjacent panels, the section being exemplarily taken in the plane indicated by line VIIVII of FIG. 1.

FIG. 8 is a schematic stress diagram showing an analysis of a dome construction composed entirely of a known hexagonal arrangement of structural frame members.

FIG. 9 is a stress diagram of a dome construction embodying the placement of pentagonally arranged structural frame members in a dome construction embodying this invention.

FIG. 10 is a fragmentary perspective view of a structural frame member used in the dome construction shown in FIGS. 1 and 2.

FIG. 11 is a sectional view in unstressed form of a gasket element used in the joint construction shown in FIGS. 6 and 7.

FIGS. 1 and 2 generally illustrate a geodesic type dome construction generally indicated at 20 embodying this invention. Dome construction 20 includes a base means 21 of generally circular form and lying in a plane. Base means 21 may comprise a plurality of base members 22 of suitable structural section and adapted to be anchored to a foundation (not shown) in well known manner.

Dome construction 20 includes a dome apex 24. Between apex 24 and base means 21 are arranged a plurality of structural frame members 25 each of the same cross-sectional configuration which is shown in FIG. 10. About the dome apex 24, frame members 25 outline a hexagonal configuration which is divided into six equilateral triangles by structural frame members 25 arranged internally of the outlined hexagonal structure. The six internal frame members 25 of each hexagonal outline are interconnected at a common intersecting area defined by circular hub means 26. Each of the triangular openings defined by the triangular arrangement of the frame members 25 may be covered by sheet material 27. In this example, sheet material 27 may be relatively thin, opague, and made of a suitable aluminum or other lightweight metal alloy. Certain of the openings framed by members 25 may be covered by translucent or transparent bubble-type or non-planar sheets of material 28 of different sectional thickness than sheet material 27.

In this example, sheet material 28 may be relatively thick in section and made of plastic material such as plexiglass or the like.

The structural arrangement and assembly of frame members 25, sheet material 27, 28 and hub means 26 are best illustrated in FIGS. 3 7 inclusive and FIGS. and 11. Structural frame member comprises a web 30, a bottom flange, 31, and a top flange 32 form ing essentially an H structural section. Top flange 32 is provided with spaced longitudinally extending parallel rib means 33. Rib means 33 includes an inner set of rib elements 34 and outer rib elements 35 spaced from the adjacent inner rib element 34 to provide upwardly facing longitudinally extending recesses 36. Each outer rib element 35 and each inner rib element 34 with the longitudinal recess 36 therebetween are of the same con figuration and for brevity the rib means on one side of the vertical plane defined by web will be described in detail.

Rib element is of less height than rib element 34 and is provided with a top flat longitudinally extending flat edge surface 38 for support of and engagement with an edge margin 39 of a sheet of material 27. Rib element 35 is provided on its inner side surface with a longitudinally extending angle section projection 40 providing a ridge line 41 for pressure contact with a downwardly turned longitudinally extending flange portion 42 provided along each edge of the triangular shaped sheet material 27. In this example, flange portion 42 may terminate in an upwardly bent longitudinally extending flange extremity 43 which is normally positioned deeply within the recess 36.

Inner set of rib elements 34 may be provided with opposed side wall surfaces 45 of longitudinally serrated configuration. The serrated surfaces 45 provide holding means for cooperable screw type fastening elements 46 which serve to secure an elongated retainer member 47 to the structural frame member. It will be understood that other types of fastening elements or means may be employed if desired.

Retainer member 47 together with a corresponding elongated gasket element 48 serve to lock and retain edge margins of sheet material 27 covering the openings on opposite sides of a structural frame member 25. Retainer member 47 is provided with the same configuration on each side of a vertical plane longitudinally bisecting retainer member 47 and only one side of said retainer member will be described for brevity. Retainer member 47 includes a bar portion 50 which extends across the inner set of rib elements 34. Along the outer edge portion of bar portion 50 is provided a depending gasket element support flange 51 which defines with the corresponding opposite flange portion 51 and bar portion 50 a central channel 52 adapted to closely slidably fit over the outer wall surfaces of the set of rib elements 34 to laterally position retainer member 47 with respect to the structural frame member 25. Flange 51 defines with an outer angularly related depending flange 53 a longitudinally extending groove means 54 for reception as a keyway of a key-like bead portion 55 of gasket element 48. The angularly disposed flanges 51 and 53 are spaced apart a selected distance slightly greater than narrow neck portion 56 of gasket element 48 to permit the endwise insertion of gasket element 48 into the keyway groove 54 from one end of the retainer member 47 during assembly of the gasket element 48 with the retainer member. Flange 51 provides an angularly disposed supporting surface 57 for the bottom surface portion 58 of the key type bead 55 of the gasket element 48. The angularly disposed supporting surface 57 lies in a plane which passes beneath the projection 40 on outer rib element 35.

Gasket element 48 includes in assembled stressed configuration, as shown in FIG. 6, a longitudinally extending triangular portion 60 which provides a wedge face 61 cooperable with wedge face 62 on the external side of flange 53. Wedge face 61 normally forms an acute angle with an external molding surface 63 which in assembly with the retainer member and sheet material 27 provides an inclined surface joining member 47 and sheet material 27 to enhance the appearance of the joint construction and to afford a tight seal between retainer member 47 and sheet material 27.

Between bead portion 55 and triangular portion 60, the gasket element 48 has an angle portion 64 having one leg of relatively thick section joining the triangular portion 60 and reducing in thickness to join the narrow throat portion 56. The intermediate portion 64 defines with triangular portion 60 a shoulder 65 of slightly concave configuration adapted to conform to and closely sealingly engage the convex configuration 66 formed by the downward bending of edge portion 42 of the edge margin 39 of sheet material 27.

As shown in FIG. 11, it will be noted that the gasket element 48 in relaxed, uncompressed form includes in cross section an enlarged portion including triangular portion 60 and intermediate portion 64 which resemble a cornucopia configuration provided with a convex external surface and including a bead portion at the small end of the configuration. The large end of the configuration provides the external molding surface 63. Wedge face 61 and bead 55 define a space which receives flange 53.

In assembled condition, FIG. 6, the relatively thick intermediate portion 64 of gasket element 48 is placed under considerable compression imparted thereto by the downward movement of retainer member 47 as it is assembled with frame member 25 and by the wedging action of flange 53 against the gasket element and toward the edge margin 39 and edge portion 42 of sheet material 27. Material of the thick portion 64 transmits pressure forces from the lower extremity of flange 53 toward the ridge-like projection 40 on rib element 35 and also toward the edge extremity of the supporting flange 51. Under such compression, the material of the intermediate portion 64 may flow downwardly into the space between the edge flange 51 and the edge portion 42 of the sheet material. Thus along the external surface of edge margin 39, and the external surface of flange 54, material of gasket element 48 is in tight pressure sealing contact to prevent leakage of water from the exterior of the dome construction to the interior thereof.

In FIG. 7, a modification of the joint construction shown in FIG. 6 is illustrated for use where the thickness of the sheet material used to cover the triangular openings is different and in this case where one of the sheet material is of thicker section than sheet material 27. Sheet material 28 as mentioned above, may be of relatively thick section plastic material such as plexiglass. In this example, the plexiglass sheet material 28 may be shaped to provide an outwardly formed bubble to collect more light for transmission through the transparent or translucent plexiglass covering. Thus, edge margin 70 ofsheet material 28 is angularly disposed with respect to the main portion 71 of sheet material 28. Edge margin 70 is received between a bottom longitudinally extending metal strip 72 and an upper longitudinally extending metal strip 73 of less width than the bottom strip 72. Bottom strip 72 is seated on the top surface of flange 32 as at 74. The top strip 73 is seated on the supporting surface 39 of rib element 35. The edge margin of strip 73 coacts with the gasket element 48 during assembly in the same manner as that above described for the coaction of edge margin 39 of sheet material 27. At spaced intervals along the length of flange 32, nut and bolt assemblies 76 secure the strips 72, 73 and the sheet material 28 therebetween to the frame member 25. Each nut and bolt assembly 76 includes a headed bolt 77, a spacer nut 78 located between the strips 72, 73 and a top locking nut 79. The spacer nut 78 may have a depth to provide a relatively loose tolerance between the opposed surfaces of strips 72, 73 so that the sheet material 28 may readily expand and contract without undue stress. Strips 72, 73 may be of angle form as shown to provide longitudinal rigidity.

Under some conditions and localities, it may be desirable to provide a band 80 of sealing material between upper strip 73 and the edge margins 70 of the sheet material 28 to minimize and eliminate leakage at edge margins of sheet material 28.

Hub means 26, 26 serves to interconnect converging end portions of structural frame members 25 at nodes or corners formed by the pentagonal and hexagonal arrangement of frame members 25, the hub means 26 shown in FIG. 3 being at the node of a pentagon. Interconnection of six frame members 25 at such a hub means 26 is virtually the same except for the angular spacing of the frame members. As best seen in FIGS. 3 5 and 10, rib elements 34 and 35 terminate at 82 in spaced relation to the end face 83 of frame member 25. End portion 84 of each frame member 25 is provided with tapered flanges 31, 32 to facilitate the assembly of five or six end portions 84 within a reduced inner node or hub area.

Hub means 26 may comprise top and bottom circular hub and gusset plates 86 and 87 of slightly convex or dished cross-sectional shape corresponding to the degree of curvature of the dome construction. Both top and bottom plates 86 and 87 may be provided with a hole pattern corresponding to the hole pattern provided in flanges 32 and 31 as shown in FIG. to permit assembly of frame members with the gusset plates 86, 87 by nut and bolt assemblies 88. As best seen in FIGS. 3 and 4, bottom plate 87 may be connected to bottom flanges 31 by nut and bolt assemblies 88 extending through bottom holes 89 in flange 31 and aligned holes 89a in bottom plate 87.

Top plate 86 is provided with a pattern of rectangu' larly arranged holes 90a for alignment with holes 90 in top flange 32. Flange 32 and top plate 86 are provided with aligned slightly outwardly disposed holes 93 adapted to be aligned with positioning holes 94 provided in sheet material 27 and serving to position a sheet material 27 with respect to adjacent frame members 25. Nut and bolt assemblies 88 extend through the sheet material, the holes in the gusset plate 86 and the holes in the flange 32. When top and bottom gusset plates 86 and 87 are assembled with the frame member end portions and the sheet material 27 of the frame members, a circular flanged cover 95 may be secured over the top plate 86 by a stud bolt 96.

In the assembly of the frame members with the hub means 26, it will be noted that the retainer bar 47 has an end face 98 which terminates in close spaced relationship to the depending peripheral flange 99 of the cover 95. Similarly, the ends of gasket elements 48 are terminated in close spaced relation to flange 99 so that a relatively small joint opening is provided between the frame member assembly and the hub means. Sheet material 27 is provided with relatively small corner cutouts 100 at vertices of the triangular sheet to facilitate location and placement of the sheet material with the hub means 26. Open space at the peripheral edges of the hub means 26 may be suitably sealed by a sealing and caulking compound 101 of well known manufacture. Such caulking compound is extended around the peripheral edge of the flange 99 to seal the joint between each sheet material 27 and the flange. The hub assembly described above provides reduced joint space to be sealed or caulked and time in assembly and maintenance thereof is substantially minimized.

The geodesic dome construction exemplified in FIGS. 1, 2 and 9 includes an arrangement of structural frame members 25 in which great circle arcs A1, A2, and A3 are formed by a line of frame members 25 passing through the apex 24 of the dome construction and terminating in the hub means 26 at the center of the pentagon formed adjacent the base means 21. While the present example shows 30 base gussets, supports, or base hub means 105, it will be understood that the same geometric arrangement of frame members may be used with 18, 24, 36, 42, etc., base gusset or hub means 105. A smaller number of base gussets will re duce the size of the dome construction while a larger number of base gussets will increase the size of the dome structure.

The placement of the pentagons at the ends of the great circle arcs Al, A2, and A3 provides an exemplary variation of a dome construction of improved stress characteristics. The differences in stressing of a prior hexagonal arrangement used in a geodesic dome construction is shown in FIG. 8. The difference in the arrangement of frame members adjacent the base means is particularly clear when FIGS. 8 and 9 are compared, FIG. 9 illustrating the pentagon arrangement. Corre' spending nodal points and frame members are identitied in FIGS. 8 and 9 which schematically shown the structural frame arrangement for one-twelfth of the dome construction shown in FIG. 1, the nodal points being identified by numbers within circles and the corresponding frame members being indicated by numbers without circles. In a stress analysis of the prior hexagonal-type geodesic dome construction shown in FIG. 8, maximum tension, not including the base ring members, is found in member 26 or T which extends between node 17 and node 12. Maximum compression in the prior geodesic dome construction occured in member 27 which extends between nodes 17 and 13, member 27 being further identified as C In the dome construction of the present invention shown in FIG. 9, maximum tension within the base means occurs in member 22, T,, extends between node 13 and node 12. Maximum compression in the structure of FIG. 9 occurs in frame member 17, C, which extends between node 9 and node 12.

In an example of dome loading of 2.5 pounds per square foot (psf) dead and 40 pounds per square foot (psf) slope graduated live loads, the reduction in structural frame member compression between the members C and C was calculated in the order of a 36.4% reduction in compression stresses. In the comparison of the maximum tension members, that is T, and T 21 calculated reduction of tension stresses was 23.3%.

It will be apparent that in the construction and assembly of a geodesic dome construction of this invention, it is very desirable that all of the structural frame members have the same cross-section since they may be formed of extruded aluminum alloy and that they have virtually the same length. The employment of pentagon arrangements at the base ring and at-the ends of the great circle arcs of the geodesic dome construction permits a dome construction to carry a larger dead load than previously possible. In addition, the improved stress distribution permits the size of the dome to be increased to carry the same specified dead load while using the same strut or frame extrusion. The reduction of stresses in the frame members carrying the heretofore maximum compression and tension stresses provides a more effective and efficient distribution of stresses in the geodesic dome construction.

It should be noted that in the above described geodesic dome construction in which the cross section of the structural frame members are the same throughout substantially all of the dome and wherein the triangular areas defined thereby are virtually uniform, that the gasket elements may similarly be extruded in the same cross sectional configuration and readily installed in each retainer member. Each gasket element 48 may be made of any suitable elastomeric material having a Shore A hardness of the approximate range of 35 50. A gasket element having such characteristics is capable of not only transmitting the pressure forces during the wedging action of' the retainer member to the edge margin of the sheet of material to effect positive retention of the sheet material, but also to provide an effective seal along the edge margins of the sheet material. It will be understood that at the hub means 26 and 26, that the caulking and sealant applied to the joint between the cover and the retainer member and other parts of the assembly is joined with the ends of the gasket element 48 to completely seal the exterior of the dome construction.

It will be understood that various modifications and changes may be made in the dome construction which may be of geodesic or non-geodesic geometry and the joint construction described above that may fall within the spirit of this invention and all such changes and modifications coming within the scope of the appended claims are embraced thereby.

I claim:

1. A joint construction for securing an edge margin of a sheet of material to a structural frame member having a top flange provided with spaced longitudinally extending rib means defining a longitudinally extending recess, one of said ribs providing surfaces for support of and engagement with the edge margin of the sheet of material, the provision of:

an elongated retainer member secured to the other of said rib means along its length;

said retainer member having side faces extending above and below the support surface of the rib means;

an elongated retainer gasket element carried by the retainer member and having an external longitudinally extending surface portion engageable with an edge margin of the sheet of material supported by said one rib means;

said gasket element extending along side faces of the retainer member and providing a molding surface between said carrier member and said sheet material to provide a seal therebetween;

said one rib means having a longitudinal ridge line contacted by said edge margin;

and means including part of said side faces on said retainer member for wedging said gasket element against said edge margin and said edge margin against said ridge line during securement of the retainer member to the other of said rib means.

2. A joint construction for securing an edge margin of a sheet of material to a structural frame member having a top flange provided with spaced longitudinally extending rib means defining a longitudinally extending recess, one of said ribs providing surfaces for support of and engagement with the edge margin of the sheet of material, the provision of:

an elongated retainer member secured to the other of said rib means along its length;

an elongated retainer gasket element carried by the retainer member and having an external longitudinally extending surface portion engagable with an edge margin of the sheet of material supported by said one rib means;

said one rib means having a longitudinal ridge line contacted by said edge margin;

and means on said retainer member for wedging said gasket element against said edge margin and said edge margin against said ridge line during securement of the retainer member to the other of said rib means;

said wedging means on said retainer member including a longitudinally extending groove means;

and said gasket element including a transverse crosssectional shape providing a longitudinal bead portion shaped generally as a quarter section of a circle for retention within said groove means,

a longitudinal triangular portion outside said groove means providing an inboard wedge face cooperable with a face on said retainer member and providing an inclined face affording an external molding surface,

said external longitudinally extending surface portion on said gasket element being provided by an angle portion of reduced cross-sectional thickness interconnecting said bead and said triangular portions, said angle portion extending between said wedge face on said retainer member and a portion of said edge marginof said sheet material for transmitting with said triangular portion pressure forces from said retainer member against said edge margins. 3. In a joint construction for securing an edge margin of stiff rigid sheet material to a structural frame member, the combination of:

a plurality of spaced longitudinally extending parallel ribs on said frame member; at least one of the outboard ribs providing a seating surface for said edge margin for supporting said stiff sheet material; said one outboard rib defining with an adjacent inboard rib a longitudinally extending recess, said outboard rib having contact means extending toward said recess; said edge margin having an edge portion extending into said recess for engagement with said contact means; an elongated retainer member having a longitudinal channel means to receive adjacent inboard ribs on said frame member, having longitudinal groove means providing a longitudinal opening facing said one outboard rib, and having an exterior wedge face above said opening; and an elongated resilient gasket element having a longitudinal inner portion received in and held by said longitudinal groove means on said retainer member and longitudinal portions outside said opening; said outside portions including an upper portion having a wedge face cooperable with the exterior wedge face on said retainer member, a lower portion interconnecting said inner portion and upper portion, said outside portions having exterior faces engagable with said edge margin of said sheet material; and means securing said retainer member to said frame member whereby as said retainer member is drawn toward said frame member, said outside portions of the gasket element are forced, as by wedging, against said edge margin to resiliently press said edge margin against said seating surface and against said contact means on said one rib. 4. In a construction as stated in claim 3 wherein said groove means on said retainer member include a longitudinal flange extending from said channel means transversely of said recess to restrict flow of said gasket element toward the bottom of the recess.

5. In a construction as stated in claim 4 wherein said groove means on said retainer member includes a longitudinal flange extending downwardly, defining the top of said longitudinal opening, and providing said exterior wedge face on said retainer member. 6. A joint construction for securing an edge margin of a sheet of material to a structural frame member having a top flange provided with spaced longitudinally extending rib means defining a longitudinally extending recess, one of said ribs providing surfaces for support of and engagement with the edge margin of the sheet of material, the provision of:

an elongated retainer member secured to the other of said rib means along its length;

an elongated retainer gasket element carried by the retainer member and having an external longitudinally extending surface portion engageable with an edge margin of the sheet of material supported by said one rib means;

said one rib means having a longitudinal ridge line contacted by said edge margin;

and means on said retainer member for wedging said gasket element against said edge margin and said side margin against said ridge line during securement of the retainer member to the other of said rib means;

said retainer member including angularly disposed flanges with one flange directed toward said recess and spaced above the other flange which is directed toward the said one rib means for defining a longitudinally extending; groove means;

and an enlarged longitudinally extending portion on said gasket element receivable within said groove means for retaining said gasket element on said retainer member.

7. In a joint construction, as stated in claim 6, the

provision of:

a resilient yieldable gasket element for sealing and retaining a bent edge margin of a rigid sheet of ma terial against a seating surface and a contact surface lying below one edge of the seating surface,

said gasket element in relaxed uncompressed form having a cross-section including an enlarged portion of cornucopia configuration having a convex exterior surface and including a bead portion at the small end of said configuration;

said gasket element in compressed configuration having the exterior convex surface deformed into a concave surface pressing against said bent edge margins supported by said seating surface and said contact surface.

8. In ajoint construction as stated in claim 6 wherein said angularly disposed flanges are at least partially re ceivable within said longitudinally extending recess on said top flange.

9. A joint construction for securing edge margins of sheets of material to a structural frame member having a top flange provided with spaced longitudinally extending rib means defining a longitudinally extending recess, one of said ribs providing surfaces for support of and engagement with the edge margin of one sheet of material, the provision of:

an elongated retainer member secured to the other of said rib means along its length;

an elongated retainer gasket element carried by the retainer member and having an external longitudinally extending surface portion engageable with an edge margin of said one sheet of material supported by said one rib means;

said one rib means having a longitudinal ridge line contacted by said edge margin;

and means on said retainer member for wedging said gasket element against said edge margin and said edge margin against said ridge line during securement of the retainer member to the other of said rib means;

said top flange being provided with said spaced rib means between and parallel to longitudinal edges of said top flange;

a bottom support strip seated on said top flange adjacent one of said longitudinal edges;

an edge margin of a second sheet of material seated on said bottom support strip;

a longitudinally extending top strip extending over whereby said edge margin of the second sheet is said edge margin of the second sheet and onto a frictionally retained between said top and bottom support surface on the adjacent rib means; strip.

and securement means for said top and bottom strips 

1. A joint construction for securing an edge margin of a sheet of material to a structural frame member having a top flange provided with spaced longitudinally extending rib means defining a longitudinally extending recess, one of said ribs providing surfaces for support of and engagement with the edge margin of the sheet of material, the provision of: an elongated retainer member secured to the other of said rib means along its length; said retainer member having side faces extending above and below the support surface of the rib means; an elongated retainer gasket element carried by the retainer member and having an external longitudinally extending surface portion engageable with an edge margin of the sheet of material supported by said one rib means; said gasket element extending along side faces of the retainer member and providing a molding surface between said carrier member and said sheet material to provide a seal therebetween; said one rib means having a longitudinal ridge line contacted by said edge margin; and means including part of said side faces on said retainer member for wedging said gasket element against said edge margin and said edge margin against said ridge line during securement of the retainer member to the other of said rib means.
 2. A joint construction for securing an edge margin of a sheet of material to a structural frame member having a top flange provided with spaced longitudinally extending rib means defining a longitudinally extending recess, one of said ribs providing surfaces for support of and engagement with the edge margin of the sheet of material, the provision of: an elongated retainer member secured to the other of said rib means along its length; an elongated retainer gasket element carried by the retainer member and having an external longitudinally extending surface portion engagable with an edge margin of the sheet of material supported by said one rib means; said one rib means having a longitudinal ridge line contacted by said edge margin; and means on said retainer member for wedging said gasket element against said edge margin and said edge margin against said ridge line during securement of the retainer member to the other of said rib means; said wedging means on said retainer member including a longitudinally extending groove means; and said gasket element including a transverse cross-sectional shape providing a longitudinal bead portion shaped generally as a quarter section of a circle for retention within said groove means, a longitudinal triangular portion outside said groove means providing an inboard wedge face cooperable with a face on said retainer membEr and providing an inclined face affording an external molding surface, said external longitudinally extending surface portion on said gasket element being provided by an angle portion of reduced cross-sectional thickness interconnecting said bead and said triangular portions, said angle portion extending between said wedge face on said retainer member and a portion of said edge margin of said sheet material for transmitting with said triangular portion pressure forces from said retainer member against said edge margins.
 3. In a joint construction for securing an edge margin of stiff rigid sheet material to a structural frame member, the combination of: a plurality of spaced longitudinally extending parallel ribs on said frame member; at least one of the outboard ribs providing a seating surface for said edge margin for supporting said stiff sheet material; said one outboard rib defining with an adjacent inboard rib a longitudinally extending recess, said outboard rib having contact means extending toward said recess; said edge margin having an edge portion extending into said recess for engagement with said contact means; an elongated retainer member having a longitudinal channel means to receive adjacent inboard ribs on said frame member, having longitudinal groove means providing a longitudinal opening facing said one outboard rib, and having an exterior wedge face above said opening; and an elongated resilient gasket element having a longitudinal inner portion received in and held by said longitudinal groove means on said retainer member and longitudinal portions outside said opening; said outside portions including an upper portion having a wedge face cooperable with the exterior wedge face on said retainer member, a lower portion interconnecting said inner portion and upper portion, said outside portions having exterior faces engagable with said edge margin of said sheet material; and means securing said retainer member to said frame member whereby as said retainer member is drawn toward said frame member, said outside portions of the gasket element are forced, as by wedging, against said edge margin to resiliently press said edge margin against said seating surface and against said contact means on said one rib.
 4. In a construction as stated in claim 3 wherein said groove means on said retainer member include a longitudinal flange extending from said channel means transversely of said recess to restrict flow of said gasket element toward the bottom of the recess.
 5. In a construction as stated in claim 4 wherein said groove means on said retainer member includes a longitudinal flange extending downwardly, defining the top of said longitudinal opening, and providing said exterior wedge face on said retainer member.
 6. A joint construction for securing an edge margin of a sheet of material to a structural frame member having a top flange provided with spaced longitudinally extending rib means defining a longitudinally extending recess, one of said ribs providing surfaces for support of and engagement with the edge margin of the sheet of material, the provision of: an elongated retainer member secured to the other of said rib means along its length; an elongated retainer gasket element carried by the retainer member and having an external longitudinally extending surface portion engageable with an edge margin of the sheet of material supported by said one rib means; said one rib means having a longitudinal ridge line contacted by said edge margin; and means on said retainer member for wedging said gasket element against said edge margin and said side margin against said ridge line during securement of the retainer member to the other of said rib means; said retainer member including angularly disposed flanges with one flange directed toward said recess and spaced above the other flange which is directed toward the said one rib means for defining a lOngitudinally extending groove means; and an enlarged longitudinally extending portion on said gasket element receivable within said groove means for retaining said gasket element on said retainer member.
 7. In a joint construction, as stated in claim 6, the provision of: a resilient yieldable gasket element for sealing and retaining a bent edge margin of a rigid sheet of material against a seating surface and a contact surface lying below one edge of the seating surface, said gasket element in relaxed uncompressed form having a cross-section including an enlarged portion of cornucopia configuration having a convex exterior surface and including a bead portion at the small end of said configuration; said gasket element in compressed configuration having the exterior convex surface deformed into a concave surface pressing against said bent edge margins supported by said seating surface and said contact surface.
 8. In a joint construction as stated in claim 6 wherein said angularly disposed flanges are at least partially receivable within said longitudinally extending recess on said top flange.
 9. A joint construction for securing edge margins of sheets of material to a structural frame member having a top flange provided with spaced longitudinally extending rib means defining a longitudinally extending recess, one of said ribs providing surfaces for support of and engagement with the edge margin of one sheet of material, the provision of: an elongated retainer member secured to the other of said rib means along its length; an elongated retainer gasket element carried by the retainer member and having an external longitudinally extending surface portion engageable with an edge margin of said one sheet of material supported by said one rib means; said one rib means having a longitudinal ridge line contacted by said edge margin; and means on said retainer member for wedging said gasket element against said edge margin and said edge margin against said ridge line during securement of the retainer member to the other of said rib means; said top flange being provided with said spaced rib means between and parallel to longitudinal edges of said top flange; a bottom support strip seated on said top flange adjacent one of said longitudinal edges; an edge margin of a second sheet of material seated on said bottom support strip; a longitudinally extending top strip extending over said edge margin of the second sheet and onto a support surface on the adjacent rib means; and securement means for said top and bottom strips whereby said edge margin of the second sheet is frictionally retained between said top and bottom strip. 